Hydrothermal liquefaction of sewage sludge; energy considerations and fate of micropollutants during pilot scale processing

WATER RESEARCH

卷:183

Article

Thomsen, Lars Bjorn Silva^1,2  Carvalho, Pedro N.^1,3  dos Passos, Juliano Souza^1,2  Anastasakis, Konstantinos^1,2  Bester, Kai^1,3  Biller, Patrick^1,2 

[1] Aarhus Univ, WATEC Ctr Water Technol, Ny Munkegade 120, DK-8000 Aarhus, Denmark

[2] Aarhus Univ, Biol & Chem Engn, Hangovej 2, DK-8200 Aarhus, Denmark

[3] Aarhus Univ, Dept Environm Sci, Frederiksborgvej 399, DK-4000 Roskilde, Denmark

关键词: Hydrothermal liquefaction;    Wastewater;    Sewage sludge;    Micropollutants;    Pharmaceuticals;    Wastewater treatment;   

DOI  :  10.1016/j.watres.2020.116101

来源: Elsevier

【 摘 要 】

The beneficial use of sewage sludge for valorization of carbon and nutrients is of increasing interest while micropollutants in sludge are of concern to the environment and human health. This study investigates the hydrothermal liquefaction (HTL) of sewage sludge in a continuous flow pilot scale reactor at conditions expected to reflect future industrial installations. The processing is evaluated in terms of energy efficiency, bio-crude yields and quality. The raw sludge and post-HTL process water and solid residues were analyzed extensively for micropollutants via HPLC-MS/MS for target pharmaceuticals including antibiotics, blood pressure medicine, antidepressants, analgesics, x-ray contrast media, angiotensin II receptor blockers, immunosuppressant drugs and biocides including triazines, triazoles, carbamates, a carboxamide, an organophosphate and a cationic surfactant. The results show that a positive energy return on investment was achieved for all three HTL processing temperatures of 300, 325 and 350 degrees C with the most beneficial temperature identified as 325 degrees C. The analysis of the HTL by-products, process water and solids, indicates that HTL is indeed a suitable technology for the destruction of micropollutants. However, due to the large matrix effect of the HTL process water it can only be stated with certainty that 9 out of 30 pharmaceuticals and 5 out of 7 biocides products were destroyed successfully (over 98% removal). One compound, the antidepressant citalopram, was shown to be moderately recalcitrant at 300 degrees C with 87% removal and was only destroyed at temperatures >= 325 degrees C (>99% removal). Overall, the results suggest that HTL is a suitable technology for energy efficient and value added sewage sludge treatment enabling destruction of micropollutants. (C) 2020 Elsevier Ltd. All rights reserved.

【 授权许可】

Free